Nghe TOEFL

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Listen to part of a lecture in an environmental science class. The professor is discussing the concept of urban heat islands. "Urban areas tend to be warmer than surrounding rural areas, a phenomenon known as the urban heat island effect. This occurs because concrete, asphalt, and buildings absorb and re-emit solar radiation more than natural landscapes do. Additionally, waste heat from vehicles and air conditioners adds to the temperature rise. The effect is most pronounced at night, when urban surfaces slowly release the heat they absorbed during the day, preventing temperatures from dropping as much as in rural areas. Several strategies can mitigate this effect. Planting trees and creating green roofs provide shade and promote evapotranspiration, which cools the air. Using reflective materials for pavements and rooftops, often called cool roofs, can also reduce heat absorption. However, these solutions require careful planning and investment. Interestingly, the urban heat island effect can have both positive and negative consequences. In winter, it may reduce heating costs, but in summer, it increases energy demand for cooling and exacerbates heat-related health risks."